Refrigeration



Dec. 29, 1942. i w. cs. KOGEL I 2,306,704

1 REFRIGERATION Filed Sept. 12, 1939 INVENT OR.

1 2 1. 1 I BY .A am

ATTORNEY.

Patented Dec. 29, 1942 Wilhelm Georg -Kiigel, Evansville, Ind.,assignor,

by mesne assignments, to Serve], Inc., New York, N. Y.,,a corporation ofDelaware Application Septcmber'12, 1939, Serial No. 294,425

((21. era-119.5)

5 Claims.

My invention relates to refrigeration and more particularly to heatoperated absorption type refrigeration systems.

It is an object of the invention to effect an improvement in operationof such systems by providing a method and apparatus .for applying heatto cause expulsion of refrigerant fluid from an absorbent, orcirculation of a liquid absorbent, orboth, in a manner to effect quickstarting of operation of the system and proper relationship ofrefrigerant expulsion and absorption liquid My invention is especiallyadvantageous in a system in which absorption liquid flow is carried outof vapor lift action, particularly when a nonvolatile absorbent isemployed.

Fig. 1 of the accompanying drawing is a more or less diagrammaticview'of a uniform pressure absorption refrigeration system embodying theinvention, and Fig. 2 is a detail sectional view on line 22 in Fig. 1.

An evaporator in the form of a pipe coil I is located in a refrigeratorcompartment The lower end of evaporator I0 is connected through theouter passage of a gas heat exchanger l2 and a conduit l3 to theupper'end of an air cooled absorber 4. An absorber vessel I5 isconnected to the lower end of the absorber coil H. The upper part ofabsorber vessel |5'is connected by a conduit l6, inner passage of gasheat exchanger l2, and a conduit H to the upper end of the evaporatorIll.

The upper end of absorber I4 is connected by a conduit l8, inner passageof a liquid heat exchanger l9, and a conduit to the lower part of avessel 2|. The upper endlof a vertical conduit 22 juts upward into theupper part of the vessel 2|. The upper end of conduit 22 is open. Abaffle plate 23 is located in vessel 2| above the open upper end ofconduit 22. The lower end of conduit 22 is connected by a conduit 24,outer passage of the liquid heat exchanger l9, and a conduit 25 to thelower part of absorber vessel |5.,

The upper part of vessel 2| is connected by a conduit 26 to the upperend of an air cooled condenser 21. The lower end of condenser '21 isconnected by a conduit28 to the upper end of evaporator Ill. The lowerend of condenser 21 is also connected by a conduit 23 to one end of avessel 30. The other end of vessel 30 is connected by a conduit 3| tothe gas heat exchanger duit 22.

has a portion in the form of a sleeve which encircles said major portionof conduit 22.

The above parts associated and connected as described form anhermetically sealed system having all parts in open fluid communicationand to whichheat may be' applied from the burner 33 through the heattransfer member 34 to con- By means of a charging plug (not shown) onabsorber vessel IS, the system is evacuated and supplied with a solutionof lithium nitrat and ammonia and hydrogen. The solution fills the lowerpart of the system to the level of the charging plug in the vessel 5,and the upper part of the system is filled with hydrogen gas and a smallquantity of ammonia vapor. The

solution is below saturation so that all of the lithium nitrate is inliquid form. The hydrogen is charged into the system at a pressure suchthat the total pressure inthe system'will be the condensing pressure ofammonia vapor at a fairly high room temperature.

In operatiomheat fromthe burner 33 is applied to the member 34 in flue32; Due to the high conductivity of member 34, the temperature of thismember increases substantiallyuniformly throughout. Heat from the member34'is transferred to'conduit 22 through the sleeve 35. So-

. 28 into the upper part of evaporator I0.

lution in conduit 22 is heated so that ammonia vapor is expelled fromthe solution. The internal diameter of conduit 22 is preferablysufficiently small that vapor and liquid have difficulty in passing eachother in this conduit, so that the ammonia vapor expelled from solutiondisplaces liquid in which it is trapped and the liquid and vapor risetogether through conduit 22 upward into vessel 2| by what is referred toas vapor lift action.

Ammonia vapor flows from vessel 2| through conduit 26 to condenser 21.Ammonia vapor is cooled and liquefied in condenser 21. Liquid-ammoniaflows from condenser 21 through conduit The liquid ammonia flowsdownward in evaporator ||l and evaporates'and diffuses into hydrogencontained in the evaporator. The resulting mixture of ammonia vapor anhydrogen gas-flow from the upper end of evap- .orator Ill throughconduit gas heat exchanger l2. Alongsideof the vertical conduit 22 is aflue 32. A gas burner 33 is located adjacent the lower end of flue 32and arranged so that the flame is projected upward into the flue. In theflue 32 there is a member 34 having an extensive heat transfer surfaceand formed of highly thermal conductive material. The member 34 isaslong as the major portion of conduit 22. Member 34 I2, and conduit Hito vessel l5 and thence into absorber coil I4. Absorption solution fiowsfrom vessel 2| through conduit 20, liquid heatexchanger l3, and conduitl8 into th upperend of absorbercoil I4. The absorption solutionfiowsdownward through coil l4 into vessel lirfAm monia vapor is absorbed bysolution flowing in 0011- I4 and vessel l5. Hydrogen gas flows from theupper end of absorber l4 through conduit l3 and gas heat exchanger 2,back to the evaporator lll. Absorption solution flows from absorbervessel l5 through conduit 25, liquid heat exchanger I9, and conduit 24back to the lower end of conduit 22.

The evaporation of ammonia in evaporator Ill produces a refrigeratingeffect for cooling air or freezing ice, or both, in refrigeratorcompartment II. The circulation in the gas circuit occurs as describedfor the reason that ammonia vapor is heavier than hydrogen gas. In thegas circuit there are two columns of gas. Gas leaving the evaporator isheavier than gas leaving the absorber-because ammonia vapor is added inthe evaporator and removed in the absorber. The production ofrefrigeration by evaporation of ammonia in the evaporator depends uponremoval of ammonia vapor from hydrogen in the absorber. Therefore, thecolumn of gas in which the absorber is connected is the lighter risingcolumn, and the direction of flow in the evaporator depends upon whetherit is connected in the rising column or the descending column.

In the liquid circuit, absorption solution flows by gravity fromvessel2l through the heat exchanger, through the absorber, and againthrough the heat exchanger to the lower end of conduit 22. The liquid islifted through conduit 22 by vapor lift action as previously described.

The vessel 30 ordinarily contains a reserve supply of hydrogen gas. Uponincrease in room temperature and necessary condenser pressure, ammoniavapor from condenser 21 displaces hydrogen from vessel 30 into the gascircuit so that the total pressure in the system increases andrefrigeration continues with condensation of ammonia vapor at acorrespondingly higher pressure.

Battle 23 in vessel 2| prevents splashing of solu-;

tion into vapor conduit 26. Due to the small diameter of conduit 22, theheat capacity of liquid in this conduit is small and, upon starting ofthe system, this liquid is quickly brought to the temperature at whichammonia vapor is expelled. Due to the uniform heating of conduit 22, byreason of the high heat conductivity and extensive heat transfer surfaceof member 34, as previously explained, a sufficient quantity of vapor isformed in conduit 22 to produce vapor lift action for causing upwardflow of liquid in conduit 22 as soon as the vapor expulsion temperatureis reached. There is therefore no overheating at any local point inconduit 22. Neither is there any appreciable vapor expulsion fromsolution in conduit 22 without movement of liquid upward in thisconduit. There is therefore no kind operated by heat including aplurality of interconnected parts forming an absorption liquid circuit,one of said parts comprising a riser tube in which liquid is adapted tobe raised by vaporlift action to cause circulation of absorbent in saidcircuit, a fuel burner removed from at least a part of said riser tubeand providing heat at a desired temperature, a vertically extending flueinto the lower end of which projects the flame produced by said burner,and structure comprising material possessing a high thermal conductivityhaving one part thereof disposed within said flue and another partembracing a major portion of the circumference of said tube, the partsof said structure within said flue and embracing said riser tubeextending longitudinally of said riser tube for a major portion of itslength.

2. In absorption refrigeration apparatus of the kind operated by heatincluding-several interconnected parts forming an absorption liquidcircuit containing an absorbent, one of said parts comprising a risertube in which liquid is adapted to be raised by vapor-liquid lift actionto cause circulation of absorbent in said circuit, a source of heatremoved from at least a part of said riser tube and providingheat at adesired temperature, structure for taking upbeat from said source andtransferring said heat in sensible form to said tube to effect heatingof the latter, said structure conductivity having one part embracing amajor portion of the circumference of said tube and plugging of conduit22 by deposit of solid lithium nitrate on account of liquid reachingsaturation at a local point in the conduit. The small diameter ofconduit 22' provides for two things, a small heat capacity generatorakin to a flash boiler for quick starting, and vapor lift action forcausing circulation of solution. The length of conduit 7 22 is such thatheat is applied to enough liquid to expel an amount of vapor per unit oftime to produce vapor lift action that will cause circulation at a raterequired by the capacity of the unit. For larger capacity units, insteadof lengthening conduit 22, a plurality of such conduits may be providedin parallel.

Various changes and modifications may be made within the scope of theinvention'which is not limited except as set forth in the followingclaims.

What is claimed is: 1. In absorption refrigeration apparatus of theextending lengthwise thereof for a major portion of its length. andanother part projecting away from said tube, and said other part beingsubjected to the heating efiect of said heat source and being moremassive than said one part to facilitate and promote rapid transfer ofheat throughout the length of said block, so that substantially uniformheating of said tube is effected kind operated by heat, a plurality ofinterconnected parts forming an absorption liquid circuit containing anabsorbent, one of said parts comprising a tube in which refrigerant isexpelled fromthe absorbent by heating, a source of heat providing heatat a desired temperature, and structure for taking up heat from saidheat source and transferring heat in sensible form to said tube, saidstructure including material possessing high conductivity having onepart embracing a major portion of the circumference of said tube andanother part contiguous to said one part, and said other part being moremassive than said one part and arranged to be subjected to the heatingeffect of said heat source to facilitate rapid transfer of heat throughsaid other part in a direction lengthwise of said tube so thatsubstantially uniformheating of said tube is readily effected by saidone part.

4. In absorption refrigeration apparatus as set forth in claim 3, inwhich said heat source constitutes a heating medium, and a member forguiding said heating medium over the surfaces of said other part of saidstructure.

5. In absorption refrigeration apparatus as set forth in claim 3, inwhich said heat source constitutes a fuel burner, and a line withinwhich said other part is disposed and into the lower end of which isadapted to project the flame produced by said burner.

WILHELM GEORG K6GE

